Blacks and Hispanics with melanoma, the potentially deadly skin cancer, tend to have it diagnosed at a later, more advanced stage than whites, researchers report.

Over the past decade, melanoma has become more common, with the rate of new cases increasing 2.4 percent every year in the United States. Because whites are at higher risk for the disease, most prevention and detection efforts have targeted them.

This may be why survival rates among whites have increased from 68 percent in the 1970s to 92 percent today. Unfortunately, the same improvement in survival hasn't been replicated among blacks and Hispanics, the University of Miami researchers noted.

"We found that patients who were black and Hispanic were diagnosed later for melanoma than white patients in Miami-Dade County, Florida," said lead researcher Dr. Robert Kirsner, professor and vice chairman of dermatology and cutaneous surgery at the University of Miami Sylvester Comprehensive Cancer Center.

Their findings appear in the June issue of the Archives of Dermatology.

In their study, the researchers looked at 1,690 melanoma cases reported in Miami-Dade County between 1997 and 2002. Among these, 1,176 occurred in white patients, 485 in Hispanic patients and 29 in non-Hispanic black patients. The population of whites and blacks in Miami-Dade County is approximately the same.

Compared with whites, the Hispanic and black patients were more likely to have advanced-stage melanomas. Sixteen percent of Hispanics and 31 percent of blacks had cancer that had metastasized -- spread to other organs or tissues -- compared with 9 percent of whites.

Moreover, 52 percent of black patients had regional or distant-stage melanoma, the most severe stages, compared with 26 percent of Hispanic and 16 percent of white patients.

Kirsner isn't sure why these differences exist. It's possible that blacks and Hispanics have a more aggressive type of melanoma, he speculated. "More likely, there is less awareness among patients and health-care providers that melanoma can occur in ethnic populations and patients with darker pigmentation," Kirsner said.

As a consequence, these patients aren't screened as often, and lesions are not detected as early as in the white population, Kirsner said. "So a diagnosis is delayed until a late stage and that correlates with worse survival," he said. "Patients' diagnoses with thin melanomas have nearly a 100 percent survival. However, if it has spread, then survival goes down to 16 percent. So survival is worse in Hispanics and blacks."

This is a public health issue, Kisner said. "Greater awareness is needed both by doctors and patients. Awareness by patients and health-care providers can, hopefully, turn that tide and lead to the same improvement in survival that has been demonstrated in white populations."

Dr. Jeffrey C. Salomon, an assistant clinical professor of plastic surgery at Yale University School of Medicine, agreed that it's important to educate blacks and Hispanics about the risk of melanoma.

"Clearly the awareness of melanoma risk in dark-skinned populations is less than in fair-skinned, sunburn-prone people. More could and should be done to raise the awareness that melanoma is not a disease exclusively of Caucasians," he said.

"Pigmentary changes on soles of feet, on palms, and under nails may be the only early warning sign of trouble in dark-skinned people," Salomon said. "This message needs to be sent out to people at risk. You can never make a diagnosis without thinking of it."

But another doctor thinks that since melanoma is largely a disease that strikes Causasians, it might be unwise to divert too many health-care dollars from education programs for whites.

"If you stop to think about how much impact you are going to have on melanoma by infusing money into the system, because melanoma is about 50 times more common in whites than in blacks, the fact is you have a lot more bang for your buck in reducing death from melanoma if that money is targeted at whites," said Dr. Jean-Claude Bystryn, a professor of dermatology at New York University School of Medicine.

Bystryn said spending the same amount of money on blacks and whites to reduce deaths from melanoma by 50 percent would save 500 lives among whites compared with 15 among blacks in Dade County.

"From a public health point of view, it is better to focus on the group that is most at risk," Bystryn said